When you make an appointment for A/C service, an auto technician will first measure the pressure in your A/C as well as the temperature output. If these readings aren't normal, then the technician will try to diagnose the problem. Your technician will look for obvious signs of a leak such as a cracked line. If there is no visible damage, he or she may use tracer dye to see where a leak is occurring. Any leaks will be repaired and fluids topped up. Your auto technician will also inspect the components of the air conditioner making sure they are in good operating condition. If necessary, they can make repairs or replace parts. These services can be performed after you discover a problem with the A/C, but annual A/C maintenance service helps keep problems at bay.